WORKERS AHEAD!
You are viewing the development documentation for the Apereo CAS server. The functionality presented here is not officially released yet. This is a work in progress and will be continually updated as development moves forward. You are most encouraged to test the changes presented.
Passwordless Authentication
Passwordless Authentication is a form of authentication in CAS where passwords take the form of tokens that expire after a configurable period of time. Using this strategy, users are asked for an identifier (i.e. username) which is used to locate the user record that contains forms of contact such as email and phone number. Once located, the CAS-generated token is sent to the user via the configured notification strategies (i.e. email, sms, etc) where the user is then expected to provide the token back to CAS in order to proceed.
Presently, there is no support for magic links that would remove the task of providing the token back to CAS allowing the user to proceed automagically. This variant may be worked out in future releases.
In order to successfully implement this feature, configuration needs to be in place to contact account stores that hold user records who qualify for passwordless authentication. Similarly, CAS must be configured to manage issued tokens in order to execute find, validate, expire or save operations in appropriate data stores.
Passwordless Variants
Passwordless authentication can also be activated using QR Code Authentication, allowing end users to login by scanning a QR code using a mobile device.
Passwordless authentication can also be achieved via FIDO2 WebAuthn which lets users verify their identities without passwords and login using FIDO2-enabled devices.
Overview
Support is enabled by including the following module in the overlay:
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<dependency>
<groupId>org.apereo.cas</groupId>
<artifactId>cas-server-support-passwordless-webflow</artifactId>
<version>${cas.version}</version>
</dependency>
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implementation "org.apereo.cas:cas-server-support-passwordless-webflow:${project.'cas.version'}"
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dependencyManagement {
imports {
mavenBom "org.apereo.cas:cas-server-support-bom:${project.'cas.version'}"
}
}
dependencies {
implementation "org.apereo.cas:cas-server-support-passwordless-webflow"
}
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dependencies {
implementation enforcedPlatform("org.apereo.cas:cas-server-support-bom:${project.'cas.version'}")
implementation platform(org.springframework.boot.gradle.plugin.SpringBootPlugin.BOM_COORDINATES)
implementation "org.apereo.cas:cas-server-support-passwordless-webflow"
}
The following settings and properties are available from the CAS configuration catalog:
cas.authn.passwordless.core.delegated-authentication-selector-script.location=
The location of the resource. Resources can be URLs, or files found either on the classpath or outside somewhere in the file system. In the event the configured resource is a Groovy script, specially if the script set to reload on changes, you may need to adjust the total number ofinotify instances. On Linux, you may need to add the following line to /etc/sysctl.conf: fs.inotify.max_user_instances = 256. You can check the current value via cat /proc/sys/fs/inotify/max_user_instances.
|
cas.authn.passwordless.core.delegated-authentication-activated=false
Allow passwordless authentication to skip its own flow in favor of delegated authentication providers that may be available and defined in CAS. If delegated authentication is activated, CAS will skip its normal passwordless authentication flow in favor of the requested delegated authentication provider. If no delegated providers are available, passwordless authentication flow will commence as usual. |
cas.authn.passwordless.core.enabled=true
Flag to indicate if paswordless authentication is enabled. |
cas.authn.passwordless.core.multifactor-authentication-activated=false
Allow passwordless authentication to skip its own flow in favor of multifactor authentication providers that may be available and defined in CAS. If multifactor authentication is activated, and defined MFA triggers in CAS signal availability and eligibility of an MFA flow for the given passwordless user, CAS will skip its normal passwordless authentication flow in favor of the requested multifactor authentication provider. If no MFA providers are available, or if no triggers require MFA for the verified passwordless user, passwordless authentication flow will commence as usual. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all
forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where
this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those
that might be presented to the system via an external library or framework such as Spring Boot, etc.
When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value.
The only possible exception to this rule is when naming actuator endpoints; The name of the
actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.
Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided
to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with
the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition
or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the
way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be
recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system
property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled
via Configuration Metadata and property migrations applied automatically on
startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be
incremented by the adopter to allow for distinct multiple configuration blocks.
Account Stores
User records that qualify for passwordless authentication must be found by CAS using one of the following strategies. All strategies may be configured using CAS settings and are activated depending on the presence of configuration values.
| Option | Description |
|---|---|
| Simple | Please see this guide. |
| MongoDb | Please see this guide. |
| LDAP | Please see this guide. |
| JSON | Please see this guide. |
| Groovy | Please see this guide. |
| REST | Please see this guide. |
| Custom | Please see this guide. |
Token Management
The following strategies define how issued tokens may be managed by CAS.
The following settings and properties are available from the CAS configuration catalog:
cas.authn.passwordless.tokens.crypto.encryption.key=
The encryption key is a JWT whose length is defined by the encryption key size setting. |
cas.authn.passwordless.tokens.crypto.signing.key=
The signing key is a JWT whose length is defined by the signing key size setting. |
cas.authn.passwordless.tokens.crypto.alg=
The signing/encryption algorithm to use. |
cas.authn.passwordless.tokens.crypto.enabled=true
Whether crypto operations are enabled. |
cas.authn.passwordless.tokens.crypto.encryption.key-size=512
The encryption key size. |
cas.authn.passwordless.tokens.crypto.signing.key-size=512
The signing key size. |
cas.authn.passwordless.tokens.crypto.strategy-type=ENCRYPT_AND_SIGN
Control the cipher sequence of operations. The accepted values are:
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cas.authn.passwordless.tokens.core.expiration=PT180S
Indicate how long should the token be considered valid. This settings supports the
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cas.authn.passwordless.tokens.crypto.encryption.key=
The encryption key is a JWT whose length is defined by the encryption key size setting. |
cas.authn.passwordless.tokens.crypto.signing.key=
The signing key is a JWT whose length is defined by the signing key size setting. |
cas.authn.passwordless.tokens.crypto.alg=
The signing/encryption algorithm to use. |
cas.authn.passwordless.tokens.crypto.enabled=true
Whether crypto operations are enabled. |
cas.authn.passwordless.tokens.crypto.encryption.key-size=512
The encryption key size. |
cas.authn.passwordless.tokens.crypto.signing.key-size=512
The signing key size. |
cas.authn.passwordless.tokens.crypto.strategy-type=ENCRYPT_AND_SIGN
Control the cipher sequence of operations. The accepted values are:
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This CAS feature is able to accept signing and encryption crypto keys. In most scenarios if keys are not provided, CAS will auto-generate them. The following instructions apply if you wish to manually and beforehand create the signing and encryption keys.
Note that if you are asked to create a JWK of a certain size for the key, you are to use the following set of commands to generate the token:
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wget https://raw.githubusercontent.com/apereo/cas/master/etc/jwk-gen.jar
java -jar jwk-gen.jar -t oct -s [size]
The outcome would be similar to:
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{
"kty": "oct",
"kid": "...",
"k": "..."
}
The generated value for k needs to be assigned to the relevant CAS settings. Note that keys generated via
the above algorithm are processed by CAS using the Advanced Encryption Standard (AES) algorithm which is a
specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology.
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all
forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where
this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those
that might be presented to the system via an external library or framework such as Spring Boot, etc.
When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value.
The only possible exception to this rule is when naming actuator endpoints; The name of the
actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.
Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided
to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with
the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition
or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the
way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be
recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system
property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled
via Configuration Metadata and property migrations applied automatically on
startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be
incremented by the adopter to allow for distinct multiple configuration blocks.
Memory
This is the default option where tokens are kept in memory using a cache with a configurable expiration period. Needless to say, this option is not appropriate in clustered CAS deployments inside there is not a way to synchronize and replicate tokens across CAS nodes.
Others
| Option | Description |
|---|---|
| MongoDb | Please see this guide. |
| JPA | Please see this guide. |
| REST | Please see this guide. |
| Custom | Please see this guide. |
Messaging & Notifications
The following settings and properties are available from the CAS configuration catalog:
cas.authn.passwordless.tokens.mail.attribute-name=
Principal attribute names that indicates the destination email address for this message. The attributes must already be resolved and available to the CAS principal. When multiple attributes are specified, each attribute is then examined against the available CAS principal to locate the email address value, which may result in multiple emails being sent. This setting supports the Spring Expression Language. |
cas.authn.passwordless.tokens.mail.from=
Email from address. |
cas.authn.passwordless.tokens.mail.subject=
Email subject line. The subject can either be defined verbaitm, or it may point to a message key in the language bundle using the syntax#{subject-language-key}. This key should point to a valid message defined in the appropriate language bundle that is then picked up via the active locale. In case where the language code cannot resolve the real subject, a default subject value would be used.
This setting supports the Spring Expression Language. |
cas.authn.passwordless.tokens.sms.attribute-name=phone
Principal attribute name that indicates the destination phone number for this SMS message. The attribute must already be resolved and available to the CAS principal. |
cas.authn.passwordless.tokens.sms.from=
The from address for the message. |
cas.authn.passwordless.tokens.sms.text=
The body of the SMS message. |
cas.authn.passwordless.tokens.mail.bcc=
Email BCC address, if any. |
cas.authn.passwordless.tokens.mail.cc=
Email CC address, if any. |
cas.authn.passwordless.tokens.mail.html=false
Indicate whether the message body should be evaluated as HTML text. |
cas.authn.passwordless.tokens.mail.priority=1
Set the priority ( |
cas.authn.passwordless.tokens.mail.reply-to=
Email Reply-To address, if any. |
cas.authn.passwordless.tokens.mail.text=
Email message body. Could be plain text or a reference to an external file that would serve as a template. If specified as a path to an external file with an extension.gtemplate, then the email message body would be processed using the Groovy template engine. The template engine uses JSP style <% %> script and <%= %> expression syntax or GString style expressions. The variable out is bound to the writer that the template is being written to. If using plain text, the contents are processed for string subtitution candidates using named variables. For example, you may refer to an expected url variable in the email text via ${url}, or use ${token} to locate the token variable. In certain cases, additional parameters are passed to the email body processor that might include authentication and/or principal attributes, the available locale, client http information, etc.
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cas.authn.passwordless.tokens.mail.validate-addresses=false
Set whether to validate all addresses which get passed to this helper. |
The following settings may also need to be defined to describe the mail server settings:
spring.mail.default-encoding=UTF-8
Default MimeMessage encoding. |
spring.mail.host=
SMTP server host. For instance, 'smtp.example.com'. |
spring.mail.jndi-name=
Session JNDI name. When set, takes precedence over other Session settings. |
spring.mail.password=
Login password of the SMTP server. |
spring.mail.port=
SMTP server port. |
spring.mail.properties=
Additional JavaMail Session properties. |
spring.mail.protocol=smtp
Protocol used by the SMTP server. |
spring.mail.test-connection=false
Whether to test that the mail server is available on startup. |
spring.mail.username=
Login user of the SMTP server. |
Configuration Metadata
The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.
Be Selective
This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.
YAGNI
Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.
Naming Convention
Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all
forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where
this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those
that might be presented to the system via an external library or framework such as Spring Boot, etc.
When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value.
The only possible exception to this rule is when naming actuator endpoints; The name of the
actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.
Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided
to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with
the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition
or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the
way you intend.
Validation
Configuration properties are automatically validated on CAS startup to report issues with configuration binding, specially if defined CAS settings cannot be
recognized or validated by the configuration schema. The validation process is on by default and can be skipped on startup using a special system
property SKIP_CONFIG_VALIDATION that should be set to true. Additional validation processes are also handled
via Configuration Metadata and property migrations applied automatically on
startup by Spring Boot and family.
Indexed Settings
CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be
incremented by the adopter to allow for distinct multiple configuration blocks.
Users may be notified of tokens via text messages, mail, etc. To learn more about available options, please see this guide or this guide.
Disabling Passwordless Authentication Flow
Passwordless authentication can be disabled conditionally on a per-user basis. If
the passwordless account retrieved from the account store
carries a user whose requestPassword is set to true, the passwordless flow
(i.e. as described above with token generation, etc) will
be disabled and skipped in favor of the more usual CAS authentication flow,
challenging the user for a password. Support for this behavior may depend
on each individual account store implementation.
Multifactor Authentication Integration
Passwordless authentication can be integrated with CAS multifactor authentication providers. In this scenario, once CAS configuration is enabled to support this behavior via settings or the located passwordless user account is considered eligible for multifactor authentication, CAS will allow passwordless authentication to skip its own intended normal flow (i.e. as described above with token generation, etc) in favor of multifactor authentication providers that may be available and defined in CAS.
This means that if multifactor authentication providers are defined and activated, and defined multifactor triggers in CAS signal availability and eligibility of an multifactor flow for the given passwordless user, CAS will skip its normal passwordless authentication flow in favor of the requested multifactor authentication provider and its flow. If no multifactor providers are available, or if no triggers require the use of multifactor authentication for the verified passwordless user, passwordless authentication flow will commence as usual.
Delegated Authentication Integration
Passwordless authentication can be integrated with CAS delegated authentication. In this scenario, once CAS configuration is enabled to support this behavior via settings or the located passwordless user account is considered eligible for delegated authentication, CAS will allow passwordless authentication to skip its own intended normal flow (i.e. as described above with token generation, etc) in favor of delegated authentication that may be available and defined in CAS.
This means that if delegated authentication providers are defined and activated, CAS will skip its normal passwordless authentication flow in favor of the requested multifactor authentication provider and its flow. If no delegated identity providers are available, passwordless authentication flow will commence as usual.
The selection of a delegated authentication identity provider for a passwordless user is handled using a script. The script may be defined as such:
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def run(Object[] args) {
def passwordlessUser = args[0]
def clients = (Set) args[1]
def httpServletRequest = args[2]
def logger = args[3]
logger.info("Testing username $passwordlessUser")
clients[0]
}
The parameters passed are as follows:
| Parameter | Description |
|---|---|
passwordlessUser |
The object representing the PasswordlessUserAccount. |
clients |
The object representing the collection of identity provider configurations. |
httpServletRequest |
The object representing the http request. |
logger |
The object responsible for issuing log messages such as logger.info(...). |
The outcome of the script can be null to skip delegated authentication for
the user, or it could a selection from the available identity providers passed into the script.